Aims To compare microaneurysm (MA) counts using ultrawide field colour images (UWF-CI) and ultrawide field fluorescein angiography (UWF-FA).
Methods Retrospective study including patients with type 1 or 2 diabetes mellitus receiving UWF-FA and UWF-CI within 2 weeks. MAs were manually counted in individual Early Treatment Diabetic Retinopathy Study (ETDRS) and extended UWF zones. Fields with MAs ≥20 determined diabetic retinopathy (DR) severity (0 fields=mild, 1–3=moderate, ≥4=severe). UWF-FA and UWF-CI agreement was determined and UWF-CI DR severity sensitivity analysis adjusting for UWF-FA MA counts performed.
Results In 193 patients (288 eyes), 2.4% had no DR, 29.9% mild non-proliferative DR (NPDR), 32.6% moderate (NPDR), 22.9% severe NPDR and 12.2% proliferative DR. UWF-FA MA counts were 3.5-fold higher (p<0.001) than UWF-CI counts overall, 3.2x-fold higher in ETDRS fields (p<0.001) and 5.3-fold higher in extended ETDRS fields (p<0.001) and higher in type 1 versus type 2 diabetes (p<0.001). In eyes with NPDR on UWF-CI (n=246), UWF-FA images had 1.6x–3.5x more fields with ≥20 MAs (p<0.001). Fair agreement existed between imaging modalities (k=0.221–0.416). In ETDRS fields, DR severity agreement increased from k=0.346 to 0.600 when dividing UWF-FA counts by a factor of 3, followed by rapid decline in agreement thereafter. Total UWF area agreement increased from k=0.317 to 0.565 with an adjustment factor of either 4 or 5.
Conclusions UWF-FA detects threefold to fivefold more MAs than UWF-CI and identifies 1.6–3.5-fold more fields affecting DR severity. Differences exist at all DR severity levels, thus limiting direct comparison between the modalities. However, correcting UWF-FA MA counts substantially improves DR severity agreement between the modalities.
Trial registration number NCT03531294.
- diabetic retinopathy
- ultrawide field imaging
- fluorescein angiography
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Contributors MAE: draft and critical revision, concept and design, acquisition, analysis. KS: concept and design, critical revision, statistical analysis. OA: acquisition, critical revision of the manuscript, technical support. AF: analysis, critical revision, technical support. JC: critical review, technical support, concept and design. AS: concept and design, critical review, administrative and technical support. SMEB: concept and design, critical review, administrative and technical support. PSS: administrative, technical and material support, supervision, concept and design, critical revision. JS: administrative, technical and material support, supervision, concept and design, critical revision, statistical analysis. LPA: obtain funding, administrative, technical and material support, supervision, concept and design, critical revision.
Funding This work was supported by Massachusetts Lions Eye Research Fund and Research to Prevent Blindness.
Competing interests PSS reports non-financial support from Optos, plc, during the conduct of the study; non-financial support and other from Hill Rom, Inc, non-financial support from Optomed Oy (ltd), outside the submitted work. JS reports grants from Research to Prevent Blindness, during the conduct of the study. LPA reports non-financial support from Optos, plc, during the conduct of the study; non-financial support from Optos, plc, outside the submitted work.
Patient consent for publication Not required.
Ethics approval The study was approved by the Joslin Diabetes Center Committee on Human Studies and adhered to the tenets of the Declaration of Helsinki.
Provenance and peer review Not commissioned; internally peer reviewed.
Data availability statement Data are available upon reasonable request. Data includes deidentified participant data, the data can be provided by the corresponding author upon request. Reuse for further publications only permitted after written permission from the corresponding author.